This invention relates to water pumps, and, more particularly, to a water pump having a bypass channel that leads from a pump inlet to a pump outlet and allows fluid entering the water pump to bypass a main impeller chamber.
Conventional water pumps are widely known and used, for example, in vehicles to circulate coolant through an engine cooling system. Typical pumps include a central chamber having an actuator-driven impeller in fluid communication with a pump inlet and a pump outlet. The impeller pushes fluid received through the pump inlet out through the pump outlet.
During operation of the pump, there is often a pressure differential between the pump inlet and the pump outlet caused by the presence, rotation and operation of the impeller. In the off state, reduction in flow equals greater pressure differential, which results in lowered operational efficiency. In the on state, the lack of gain in flow equals greater pressure differential resulting in a lowered operational efficiency. If the pressure differential becomes too large, the operation of the engine cooling system, for example, and various components within the engine cooling system may not function as desired.
Conventional pumps can be designed with a spacing or gap between the impeller and an inner surface of the central chamber to alleviate some of the pressure differential. Undesirably, the spacing causes turbulence in fluid flow within the central chamber, which interferes with operation of the impeller and reduces pumping efficiency.
Accordingly, a fluid pump that minimizes the pressure differential without significantly negatively effecting impeller operation is needed.